This document provides an overview of drillstring equipment used in drilling engineering. It discusses the components that make up the drillstring, including drill pipes, drill collars, heavy wall drill pipes, tool joints, and elevators used to handle the drillstring. Drill pipes extend along most of the drillstring length and are used only under tension to transmit power. Drill collars are thick-walled pipes located near the bit that provide weight to apply axial force to the bit. Heavy wall drill pipes are intermediate between drill pipes and collars, able to withstand compression and used in directional drilling.

1. Drilling Engineering 1 Course (2nd Ed.)

2. 1. The Rotary System
A. Introduction
B. Kelly, Kelly Valves, and Kelly Saver Sub
C. Rotary Table and Components
2. Well Control System
3. Well Monitoring System

3. 1. Drillstring Tubulars
A. Drill Pipes
a. properties of drill pipes
B. Drill Pipe Elevator
C. Drill Collars & Heavy Wall Drill Pipes

5. Drillstring purpose & constitutes
The purpose of the drillstring is
to transmit mechanical power (torque and rotation),
hydraulic power (pressure and flow rate), and
weight to the bit.
The drillstring is composed mainly
of the following elements:
Drill pipes,
Heavy wall drill pipes,
Drill collars,
Several special elements and tools.
Spring14 H. AlamiNia Drilling Engineering 1 Course (2nd Ed.) 5

6. schematic of a typical rotary drillstring
Spring14 H. AlamiNia Drilling Engineering 1 Course (2nd Ed.) 6

8. Drill Pipe
Below the kelly assembly
(upper kelly valve + kelly +lower kelly valve + kelly saver
sub) is a length of drill pipes (DP).
Drill Pipe is a primary and important drillstring member.
Since the drill pipes are generally compose
the upper and longest portion of the drillstring,
they must be light and strong.
The drill pipe body is a seamless pipe
with outside diameter (OD) varying from 2 3/8in to 6 5/8in.
The outside diameter and the wall thickness t
determine the linear weight of the drill pipe.
The inside diameter (ID) is equal to OD minus 2t.
Spring14 H. AlamiNia Drilling Engineering 1 Course (2nd Ed.) 8

9. Drill pipe material
Drill pipes are made of
high grade steel
(there are also drill pipes made of
aluminum, carbon fiber, etc).
API has standardized four steel grades:
E–75, X–95, G–105, and S–135.
The figures represent
the minimum yield strength Ys
(in ksi) of the the steel.
Spring14 H. AlamiNia Drilling Engineering 1 Course (2nd Ed.) 9

10. Drill pipe specification and
following basic parameters
Drill pipes are specified with the following basic parameters:
1. Length range:
Range I: 18ft to 22ft,
Range II: 27ft to 30ft (most common),
Range III: 38ft to 45 ft,
2. Nominal linear weight:
in general 2 or 3 linear weight or wall thickness for each standard
OD
3. Wall upset:
EU (external upset), IU (internal upset),
and IEU (internal & external upset).
The wall upset is a length of extra thickness at both ends of the drill
pipe body to provide a smooth transition between the pipe body
and the tool joint, in order to reduce the stress concentration,
Spring14 H. AlamiNia Drilling Engineering 1 Course (2nd Ed.) 10

11. Drill pipe specification and
following basic parameters (Cont.)
4. Tool joint OD, ID, and tong length,
5. Steel grade:
(D-55), E-75, X-95, G-105, S-135,
6. Connection size and type:
from 2 3/8in to 5 1/2in, type
IF (internal flush),
EF (external flush),
FH (full hole),
XH (extra hole),
SH (slim hole),
DS (double streamline), and NC (numbered connection),
The API RP-7G contains the specification of all API
standard drill pipes approved for oil and gas drilling use.
Spring14 H. AlamiNia Drilling Engineering 1 Course (2nd Ed.) 11

12. The tool joints
The tool joints
are heavy coupling elements having coarse,
tapered threads and sealing shoulders designed
to sustain the weight and
to transmit torque along the drillstring.
The threads of the tool joints are specially designed
to offer strength (axial and torsional), easy handling,
fast connections (number of turns to make the
connection), and leak-proof sealing (metal to metal).
Tool joints might be
welded or screwed to the ends of the drill pipe body.
Spring14 H. AlamiNia Drilling Engineering 1 Course (2nd Ed.) 12

13. Typical tool joint designs
(A)
Internal upset DP
with full–hole
shrink–grip TJ,
(B)
External upset DP
with internal–
flush shrink–grip
TJ,
(C) External upset
DP with flash–
weld unitized TJ,
(D) External–
internal upset DP
with Hydrill™–
pressure welded
TJ.
Spring14 H. AlamiNia Drilling Engineering 1 Course (2nd Ed.) 13

15. common properties of drill pipes
Two other common properties of drill pipes are
capacity and displacement.
Pipe Capacity:
The capacity Ap of a drill pipe is a measure of
its internal area, expressed as volume/length,
usually gal/ft or bbl/ft.
Sometimes the capacity is expressed as the reversal of the area,
usually in ft/bbl. The reader should be attended to the units.
If Di is the inside diameter (ID) of a drill pipe in inches,
then
Spring14 H. AlamiNia Drilling Engineering 1 Course (2nd Ed.) 15

16. common properties of drill pipes
(Cont.)
Pipe Displacement:
The displacement As of the drill pipe is the measure of its
cross-section area, expressed as volume/length, normally
bbl/ft.
If Do is the outside diameter (OD) of a drill pipe in inches,
Annulus Capacity:
The annulus capacity Aa is not a property of the pipe because
it depends on the diameter of the hole opposite to the pipe.
DW is the diameter of the well, & the annulus capacity Aa in bbl/ft
Spring14 H. AlamiNia Drilling Engineering 1 Course (2nd Ed.) 16

17. Drill pipe nominal weight
The capacity and displacement formulas above
do not take into account the tool joints,
and manufacturer tables must be consulted
when more accurate values are required.
In particular, the nominal weight that specify a
given drill pipe represents
neither the pipe body linear weight,
nor the average linear weight
(body plus tool joint divided by its length).
It is just a nominal value.
Spring14 H. AlamiNia Drilling Engineering 1 Course (2nd Ed.) 17

18. adjusted linear weight of the drill
pipe
a typical 5in DP with 19.5 lb/ft has an internal
diameter of 4.276in.
The density of steel is 489.5 lb/ft3.
Therefore, one foot of pipe body weights
Considering a 30 ft long DP (Range II), the tool
joints (pin and box) comprise about 2 1/2 ft of its
length.
Outside and inside diameters of the tool joints are 6in
and 3 1/2 in respectively.
Spring14 H. AlamiNia Drilling Engineering 1 Course (2nd Ed.) 18

19. adjusted linear weight of the drill
pipe (Cont.)
Therefore, the linear weight of the tool joint is
The weight of the drill pipe (body plus TJ) is
Consequently,
the adjusted linear weight of the drill pipe is
Spring14 H. AlamiNia Drilling Engineering 1 Course (2nd Ed.) 19

20. DP Classification according to wearing
Drill pipes are subjected to wear during operation.
In particular,
reduction of tool joints OD and wall thickness
reduce tensile and torsion capacity of the element.
Used drill pipes are classified as
Premium or Class I
if the minimum wall thickness is at least 80%
of the wall thickness of a new pipe, and
A new pipe that for the first time is connected to a drillstring is
immediately re–classified to premium DP.
Class II when at least 70%.
Spring14 H. AlamiNia Drilling Engineering 1 Course (2nd Ed.) 20

21. New Drill Pipe Dimensional Data
The table
presents
dimensional
data for new
drill pipes.
Drill Pipe
Dimensions
(as in API
RP7C)
Spring14 H. AlamiNia Drilling Engineering 1 Course (2nd Ed.) 21

24. drill pipe elevator
Drill pipes are handled during tripping using a drill
pipe elevator.
(The swivel and kelly are set aside in the rat hole.)
It is connected by two links to the hook body.
A hinge and latch allows opening and closing the
bi–parted collar around the drill pipe.
The elevator is operated
by the roughnecks at the rotary table level, and
by the derrick man at the monkey board.
Spring14 H. AlamiNia Drilling Engineering 1 Course (2nd Ed.) 24

25. A DP elevator and the links to the
hook body
Spring14 H. AlamiNia Drilling Engineering 1 Course (2nd Ed.) 25

26. Drill pipes
Drill pipes extend
across almost the whole length of the drillstring and,
although relatively light, they contribute with a significant
part of the drillstring weight (50% or more).
However, drill pipes are, in general,
used only under tension.
They should not be subjected to compression
due to its low resistance to buckling.
Therefore, they cannot be used to apply weight on the bit.
• In horizontal wells, drill pipes can be put under compression
if located in a suitably curved section of the hole; in addition,
compression service drill pipes
(CSDP, S-135 grade DP with 2 or 3 wear knots) are specially designed
to work under compression to drill short radius horizontal wells.
Spring14 H. AlamiNia Drilling Engineering 1 Course (2nd Ed.) 26

28. Drill collars role and specifications
Since drill pipes
cannot be used to apply weight on bit,
this role is played be the drill collars
(and also by heavy weight drill pipes as shown next).
Drill collars (DC)
are thick walled steel pipes
located normally right above the bit, and
purpose is to provide weight (axial force) to the bit.
are manufactured with carbon steel (AISI 4115), or
some non-magnetic alloy (stainless steel, monel metal).
Spring14 H. AlamiNia Drilling Engineering 1 Course (2nd Ed.) 28

29. A spiraled and a slick drill collars
The outside of drill collars may
be slick (small diameters) or
spiral grooved (any size.).
The purpose of the groves is to
reduce or avoid the risk of
differential sticking opposite to
permeable formations.
The depth of the grooves is made
larger than the average thickness
of a flocculated mud.
Average length of drill collars is
34 ft, but re–threading normally
makes them shorter.
Spring14 H. AlamiNia Drilling Engineering 1 Course (2nd Ed.) 29

30. Drill collars elevators
The elevators for drill collars are very similar to the
elevators for drill pipes.
They differ in the shape of the internal hole that clamps
on the pipe.
Most drill collars are recessed so as to be handled with
the elevator.
If the drill collar is not recessed (sometimes even if it is!),
a special sub called lift sub is used.
Lift subs have the shape of the upper end of a drill pipe, and
connects to the top of sections of drill collars during trips.
• Then the drill pipe elevator can be used to lift or lower the
drillstring.
Spring14 H. AlamiNia Drilling Engineering 1 Course (2nd Ed.) 30

31. heavy wall drill pipes (HWDP)
In addition to drill pipes and drill collars, there are
special pipes called heavy wall drill pipes (HWDP).
They are intermediary pipes between drill pipes and drill
collars,
being strong enough to be put under compression
(they contribute to the available weight
to apply to the bit), and
they are flexible enough to be used in directional drilling (less
torque and drag than drill collars.)
The use of HWDP also
allow a gradual transition
between the flexible drill pipes and the stiff drill collars
(less stress concentration, and
therefore, less mechanical fatigue on the threads.)
Spring14 H. AlamiNia Drilling Engineering 1 Course (2nd Ed.) 31

32. Heavy wall drill pipes
HWDPs look very similar to regular drill pipes,
being of the same length of Range II DP (27 to 30 ft),
but with longer tool joints (to permit re–threading).
HWDPs have a central external upset.
it provides an additional third point of contact,
increasing the overall stiffness and protecting the pipe
sections from excessive wearing in high inclination wells
(normally the tool joints and central upset have a band
of hard material to prevent/reduce wear).
Spring14 H. AlamiNia Drilling Engineering 1 Course (2nd Ed.) 32

33. 1. Jorge H.B. Sampaio Jr. “Drilling Engineering
Fundamentals.” Master of Petroleum
Engineering. Curtin University of Technology,
2007. Chapter 3

34. 1. Drillstring Equipment
A. Special Tools
2. Connections; Make–up and Break–out
3. Other Drillstring Equipment